


he is not my kid, dammit

by antukini



Series: sleepy does camp nano april 2020 [16]
Category: Naruto, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Attempt at Humor, Crossover, Dimension Travel, Gen, bakugou in particular in this one, calmer bakugou, mostly hashirama, ppl think bakugou is tobirama's kid, tobirama being soft for kids
Language: English
Status: Completed
Published: 2020-04-16
Updated: 2020-04-16
Packaged: 2021-03-01 23:27:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,666
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23685403
Author URL: https://archiveofourown.org/users/antukini/pseuds/antukini
Summary: “Are you sure he’s not your child, brother?” Hashirama squinted at the unconscious light blond teenager laying on the couch inside the Hokage’s office.
Relationships: Senju Hashirama/Uzumaki Mito, Senju Tobirama/Uchiha Madara (Pre-relationship)
Series: sleepy does camp nano april 2020 [16]
Series URL: https://archiveofourown.org/series/1686649
Comments: 5
Kudos: 395





	he is not my kid, dammit

**Author's Note:**

  * For [Ser_Thirst_A_Lot](https://archiveofourown.org/users/Ser_Thirst_A_Lot/gifts).



> prompt fill for louiserandom on tumblr who requested: *snorts* Bakugou ends up in ninja world and everyone assumes he's Tobirama's son lmao (OP fire release tho, and everyone's like?? huh??? how does this kiddo have stronger fire jutsu than the Uchiha???? Tobirama what you ain't telling us?)
> 
> didn’t complete all the parameters but uhhh have this dhfgshdf y'all i blanked on what bkgo and the founders could have done in the interim before bakugou went home so hhhh
> 
> m(_ _;)m i don’t think i got hashirama’s voice right …i also don’t know how to write fight scenes
> 
> i’m thinking the bakugou would be in his second-year in this so he’s calmer

“Are you sure he’s not your child, brother?” Hashirama squinted at the unconscious light blond teenager laying on the couch inside the Hokage’s office. He had just finished healing the small scratches on the boy when Tobirama bid him.

Tobirama let out a hard sigh, having already told him his answer what felt like a hundred times. His patience is running thin. “Anija, I assure you that anyone I have had relations with in the past had no way of conceiving a child.”

“But he looks so much like you! The younger you!” Hashirama turned to give him a pout but then paused in the middle of the action, eyebrows scrunched, making him look even more stupid than usual, almost as stupid as what came out of his mouth next. “Is he _a test tube baby you made_?!” He whirled around to point tearing eyes and an accusing finger at his younger brother, mouth wobbling in assumed betrayal.

“I have _not_ , anija. I haven’t dabbled in genetics. I wouldn’t have hidden him from you if I had. Furthermore, the child’s physical age doesn’t even make sense, if he were my lovechild I would have been _thirteen_ , brother, and his chakra doesn’t even feel even a _bit_ like mine.” Tobirama furiously scrubbed at his face. This is it, he is feeling his braincell count declining just listening to his brother’s inane theories. He hoped Mito got here faster.

Tobirama mused on the circumstances that lead them to this point in a mildly successful attempt to drown out Hashirama’s stupidity entering his ears.

_Tobirama and Hashirama were having their usual weekly morning sparring session in their chosen training ground in Konoha. The sun had started peeking out when they started and was now beating rays of light on the side of their heads._

_Faint quakes resounded throughout the training ground as they sparred._

_Spin. Kick. Punch. Evade. Drop. Roll. Jutsu. Sprint. Repeat._

_Tobirama made a single hand sign to counter the Mokuton Shield Hashirama erected. Water bullets hit the center in quick succession, weakening it as he ran forward. Gathering and condensing chakra in his fist, he punched through the shield, another jutsu ready in his other hand._

_They didn’t get to continue when they suddenly had to take cover from a sudden flash of light between them. Hashirama hastily erected a shield and Tobirama used Hiraishin to get behind a rock he’d tagged earlier._

What was that? _Tobirama kept his senses focused on the anomaly. It seemed… unfamiliar. What he sensed in that quick flash of light felt like one of his space-time experiments, only this one had a distinctly unfamiliar flavor. The new arrival didn’t feel like it_ fit _the world,_ this _world. At this, he was at least eighty-percent sure he knew what was going on but he still needs more information to be certain._

_Sensing that whatever had appeared in the middle of their spar didn’t even have_ any _chakra coils, Tobirama judged it to be safe enough to peek out the boulder he took cover behind. It seemed Hashirama had the same idea as he peeked around his wooden shield._

_The sight that greeted them was an exhausted-looking teenager with light blond hair with red eyes wearing odd clothing opening their mouth to say “What the fuck?” in an unfamiliar dialect but was understandable enough with a distinctly male voice and then promptly went unconscious just as soon as the words got through his mouth._

_Tobirama didn’t sense any dangerous stirring around the teenager who he suspected might be from a different dimension if his deductions were right and so was unhesitant in walking up to the unconscious body in the middle of the training ground, he trusted his instincts. The teen’s body had at least fallen backward, saving him from an unpleasant bruise to his face._

_The teen—he felt more like a child actually, as young as his students—was breathing alright. Lightly battered but didn’t seem to have any pressing injuries, no need to bring to the hospital. Probably exhausted as well if the child’s earlier posture wasn’t betraying anything. Perhaps bodily strain from being transported to his home dimension? Hm._

_Tobirama shot a look at his brother, considering. He suddenly crouched to take the child on his back. “Are you just going to stare there, anija, or are you going to help me take the child to your office?” He stood up, the child secure behind him, giving his brother a pointed look._

_That got Hashirama out of his stupor, uncharacteristically giving a quiet nod._

_Hm. Odd._

_Tobirama chose to put it out of his mind to focus on getting them to the Tower._

_The brothers took to the rooftops, navigating foot traffic would be a nightmare as of this time with the morning markets already open and bustling._

_He had hoped taking the rooftops would mitigate possible rumors of the child but when he hears someone murmuring about him and the child he was carrying before he pushed off to another rooftop, it looks like those hopes were dashed. The village will probably be buzzing about his human cargo in minutes._

Tobirama was jarred out of his recollection of the past hour that had led them here by another loud theory from Hashirama.

“What if he was made by enemy shinobi who found out how fond you are of children and made him look like you to garner more sympathy?” Hashirama punched his palm, a triumphant look in his eyes as if he’d figured it out entirely. He did not.

Too tired to even waste any more energy contradicting his brother, he instead said, “Perhaps _waiting_ for the child to wake and answer our questions will be better than making up baseless theories, anija. And anyway, the child doesn’t feel like he’s from here. I have a plausible theory which,” he said before Hashirama could start demanding for him to share his theory, “I will only divulge when Mito gets here or when the child wakes.” Tobirama felt quickly-approaching chakra signatures that felt like _hearth-feathers-flames_ and _seabreeze-salt-composedmischief_. It looked like his wishes were being answered.

Hashirama opened his mouth to most likely protest or perhaps speak out another baseless theory when the office door opened with a loud _bang_.

Fortunately, it drowned out Hashirama’s voice.

_Un_ fortunately, it woke their young guest from his unconsciousness who then proceeded to shoot explosions out of his hands.

A hasty but no less elegant gesture immediately doused what could have burned Hashirama’s face off—though Tobirama was confident that Hashirama’s regeneration would heal him just fine but would rather not put up with the whining.

The Senju brothers and the new arrivals turned to look at the teenager in a corner of the office, fortunately not near the window, an escape would be most troublesome and would probably add to his headaches in quelling the rumor mill after this incident.

“I came with Mito as soon as I heard you were taking home your kid on your back from the gossiping old biddies while I was shopping for your fish,” Madara drawled quietly when he drew up near Tobirama, eyes trained on the child sequestered in the corner, hands giving out small pops of small explosions. Interesting.

Tobirama closed his eyes for a moment to gather himself. _Depths give me strength._ “He is _not my child_ ,” he grits out. “We should perhaps calm the child first before we address the rumors, yes?”

“Who the fuck are you people and where am I?” the teenager demanded, eyes fierce and his body in a ready stance.

No one is going to get answers with such hostility in the air so Tobirama talked with a calming voice instead of screaming from his frustration. “I am Senju Tobirama and you are in Konoha in the Hokage Tower. Beside me is my brother, Hashirama; Uchiha Madara; and Uzumaki Mito, my brother’s wife.” He pointed them out as he introduced them by name. “My brother and I were sparring when you suddenly appeared in a flash of bright light. We brought you here to let you rest and answer some questions so we may help you get back to where you came from.” The tension lessened. Even he had calmed _himself_ with his tone, he mentally patted himself on the back.

“Bakugou Katsuki,” the teen said gruffly, standing in a less threatening stance.

“Would you be amenable to sit on the couch instead so we may speak in more comfortable positions, Bakugou-san?” When the child— Bakugou’s eyes started taking on a defiant light, Tobirama then said, with a strong pulse of chakra, “I swear on _my honor_ that _none_ of us will harm you.” None of them wanted to hurt any child, they could harmlessly restrain him if they had to take action.

That got Bakugou to consider. Good. Hashirama even projected a welcoming air to calm the suspicious child down. Mito and Madara stayed quiet but unthreatening, they’re not particularly good at calming children.

After a few tense moments, Bakugou finally relented and sat on the couch the farthest from them. At least he didn’t look cornered anymore, Tobirama supposes.

“Would you tell us how you got here?” Tobirama prodded as it seemed Bakugou wasn’t going to take initiative, still antsy at the situation. Tobirama understood.

“Got hit by a quirk that sends someone to alternate realities. I was told it would wear off in five hours. How long have I been unconscious? How long has it been since I got here?” Bakugou said, arms folded and cheeks puffed angrily, not unlike Madara in a snit actually.

Quirk? And alternate realities, huh? Interesting. That answered his question about their reality possibly being only one of many. He shook himself out of that train of thought, shelving it for a later date.

It looked like they didn’t have to do anything. Good, they didn’t have to risk the child’s existence with a dimension-hopping seal and potentially sending him off to the wrong reality.

“You appeared here two hours ago, that leaves three hours. Are you hungry?” Tobirama assumed the strain the body had to go through for the inter-dimensional trip would lead to needing sustenance. The child was also a guest, it wouldn’t do for them to let him be unwelcome. He was also a child and woe betide those who mistreat a child in Tobirama’s presence.

“I’m no—” As if it was waiting for the most comedic timing, Bakugou’s stomach grumbled loudly, prompting Hashirama to laugh loudly. Bakugou couldn’t seem to decide to glare at either his stomach or Hashirama.

“I’ll send for a runner to get us some food,” Mito said as she walked out to intimidate a passing runner. She’ll be back, she and Tobirama had been throwing the idea of alternate realities only months before, and was sure to have questions.

As they waited for food, Tobirama and Mito grabbed the opportunity to question Bakugou about his reality.

The world sounded interesting. Heroes and villains instead of shinobi; technologies much more advanced than those in Tetsu no Kuni; multiple continents instead of just one; over a hundred countries compared to their own less than twenty; firepower far more destructive than theirs—though Tobirama was pretty sure someone could devise them—; a relatively more peaceful society than theirs; quirks instead of jutsu, though it seems taijutsu was still practiced; . Bakugou, more relaxed at this point, had been surprised to learn that they had a daimyo, saying that the last daimyos in his alternate reality were turned into governors around three hundred and fifty years ago. It seemed there were some similarities to their cultures at least.

Even when the runner arrived with food and they started eating—Tobirama was sort of glad that they had nothing pressing to attend to today, he was already deeply invested in learning about this reality so different from theirs—, the conversation kept going. Tobirama and Mito mostly drove it but Hashirama and Madara threw in their occasional ryo. Hashirama was a bit quieter than usual though, trying to subtly scrutinize their guest. He’ll blurt out his thoughts soon enough.

It made him want to take a vacation to study it in person. From the look on Mito’s face, she agreed with his sentiment.

When they passed the four and a half hour mark as they exchanged information, Hashirama finally opened his mouth to air out what’s been on his mind since he had been scrutinizing the boy.

“Are you sure he’s not your test tube baby? He’s awfully similar to you and Madara.”

Tobirama gazed up into the sky as Madara spluttered beside him. _Depths give me strength._

“Me?! And your brother?! No— _Never!_ ” That’s an awful lot of denial. That sound was also similar to what Izuna referred to as his brother’s ‘in denial’ voice. Tobirama directed a raised brow at Madara to convey his disbelief and saw the Uchiha’s face neck almost completely red.

Hm. Interesting. Something to consider. But later.

“Anija, we have not even _had_ relations. Bakugou-san has already told us where he is from. Stop these inanities, I implore you.” Tobirama’s face couldn’t be more deadpan than an actual pan that had been beaten to death.

“But he’s so similar—”

“I am well-aware of his similarities to me in looks and temperament and Madara as well. It does not mean he is at all related to me.”

“But—” Hashirama tried to sway him with his wobbling bottom lip but Tobirama has built an immunity to it after years of exposure.

“But nothing. Shut up.” Tobirama sipped his tea. It was almost time for Bakugou to return.

They sat in silence with their tea, except Hashirama who was sulking in a corner, until Bakugou broke the silence.

“Thanks for taking care of me even though I almost blew your face off,” Bakugou grumbled at the floor.

Tobirama couldn’t help the unbidden smile crossing his face. “It was no problem at all. I am glad we were able to talk it out civilly.”

At this, Bakugou barked out a laugh. “Kinda glad it was me and not a younger me who got here.”

Tobirama raised a brow and opened his mouth to ask but felt the air shifting. It was time.

“It seems this is goodbye, Bakugou-san. It was nice talking with you.” Tobirama set his tea down and nodded his head in lieu of a bow.

Bakugou bowed slightly in return as he stood. “Thank you for your hospitality.”

“Take care of yourself over there, brat. Try not to get sent to other dimensions, you might not be lucky next time,” Madara said with a teasing grin. Bakugou’s face scrunched with a scowl and a glare.

“Goodbye, Bakugou-kun! Take care!” It seems Hashirama has already gotten himself out of his sulk, plucking the mushrooms that had grown on him from his wallowing.

“Goodbye, Bakugou-san. Thank you for telling us about your world,” Mito, as regal as ever, said with a nod.

Then, light flashed so brightly they had to look away lest they be blinded. When they looked back, Bakugou was gone.

“Well, then.” Tobirama stood, brushing his clothes. “I shall take my leave, my students are waiting. Don’t forget you still have papers to get through today, anija.” He ignored Hashirama’s exaggerated groan.

He turned to Mito with a nod. “Aneue.”

Tobirama went to leave but stopped a step away from the door to regard Madara. Hm. “Care to join, Madara? I’m sure my students have missed you throwing them around.” He’ll corner him later.

As he made his way to the training grounds he and his students frequent with Madara in tow, he thought about how he was going to quell the rumors of his supposed “son” but then smirked to himself as another thought came to mind.

How unfortunate that Izuna wasn’t here to join in on the occasion. He can already hear him whining about not being here for this.

**Author's Note:**

> the tumblr post of this prompt fill is [here](https://antukini.tumblr.com/post/615573378096627712/snorts-bakugou-ends-up-in-ninja-world-and)
> 
> shit now i’m thinking about tobirama dabbling in alternate reality-hopping seals and then whoops drops himself in bnhaverse (and possibly kicking lov ass why not). lou i hope you’re happy
> 
> wow this is longer than the last fills fhksjdfh
> 
> I wasn’t able to include ppl wondering abt his firepower bcos he was unconcious and they kept him inside the office sorryyyyy
> 
> why was madara buying tobirama fish? izuna probably roped him into it since he’s gone for the week on a mission. tobirama can’t go to the market at that time bcos of the spar and the foot traffic so he asks izuna to do it for him since he usually shops at that day and time anyway (at least that’s the reason I’m going with)
> 
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